function timer(intDiff){

    var intDiff = parseInt(4210); //倒计时总秒数量
    var hour=0,
        minute=0,
        second=0;//时间默认值

    window.setInterval(function(){

        if(intDiff > 0){
            hour = Math.floor(intDiff / 3600) ;
            minute = Math.floor(intDiff / 60) - (hour * 60);
            second = Math.floor(intDiff) - (hour * 60 * 60) - (minute * 60);
        }
        if (hour <= 9) hour = "0" + hour; //格式设置
        if (minute <= 9) minute = "0" + minute;
        if (second <= 9) second = "0" + second;
        $('#time_show').html(" "+hour+":"+minute+":"+second+"");
        intDiff;
    },1000);
}